make menuconfig
ATA,IDE...->IDE,ATA->Use PCI DMA by default when available

the help talks about some problems with certain boards, but well it works for me.

Cya lX

breaking 30Mb/s, well I have the quantum fireball 30Gb/AS which beats the 30Mb limit, but remember harddisk heads go from outer to inner ring, and on innerring there's less room so at the end of the harddisk I fall under the 30Mb/s think it's about 35 -> 28 Mb/s._________________"Remember there's a big difference between kneeling down and bending over.", Frank Zappa

You can also enable automatic DMA on startup for specific devices, adding commands to your kernel append line.

by IDE channel, for both master and slave, ide#=dma
by drive, hdx=dma

All will automatically try for the best possible mode for the drive/controller. In case this causes any problems, I would advise you copy your current settings to a separate backup menu entry, and add the extra settings to the first. Better than digging out your rescue disk.

Contrary to what you might think this chipset was not fully supported until recently, when code submitted by Vojtech Pavlik was incorporated into the 2.4.19-pre9.patch . None of the kernels that you can emerge through portage have that patch, so if you want full support for that chipset you have to build your own patched kernel. Keep in mind that this patch is a work in progress.

So what you need to do is emerge vanilla sources, then head over to ftp.kernel.org get 2.4.19-pre9.patch and apply that patch to the vanilla sources.

Optionally you can also get the pre-emptive kernel patch and apply that AFTER you applied the patch mentioned above.

I did this and my system (Soyo Dragon +, kt266a/VT8233CE) runs smoother than ever:)

Assuming that you are running as root, and using a motherboard with a fairly recent chipset in it (in my case, a via8233a), the problem is that the linux kernels in the portage tree (I was using xfs-sources) do not recognize the new chipset. They then default to a Generic PCI IDE controller behavior, which does not support DMA.

Is your chipset fully supported and configured in your kernel? Also, some people make the mistake of putting two harddrives on one ide controller in a master/slave configuration. One ide-channel per drive is best, otherwise you'll get decreased performance regardless of proper dma/chipset configuration.

This has been asked once before, but is there any way to tune SCSI hard drives? The only thing I've found is a mention of using module parameters to enable TCQ, but I don't have my adapter loaded as a module.